USING 5W-20 WHERE NOT SPECIFIED

Eddie · Mar 7, 2006

One would expect a good uoa when using any top tier synethic for only 3,000 miles. This is no usefull information other than the engine was not self distructing. JMO

ToyotaNSaturn · Mar 7, 2006

Pennzoil 5w20 SM used in at ten year old Saturn. Works great! No consumption!

I have a UOA of Pennzoil 5w-20 SM Synth a while back. Again, great results! The engine did consume some oil.

I wonder why the engine consumed the synth and not the dino?

Either way, I wouldn't hesitate to use 5w-20 in most cars on the road nowadays.

PJH · Mar 7, 2006

Is everyone running 5w20 winter and summer?
Much diff with 20 vs 30 in the summer?
Our 03 Honda Civic calls soe 5w20 while my Protege5 says 5w30/10w30
Would like to just buy "1" oil (usually Penn Dino)

MolaKule · Mar 7, 2006

quote:

Has anyone else noticed increased consumption using 5w20 where not Spec ?

Yes, 2.4L Nissan Frontiers with small sumps.

Dagwood · Mar 7, 2006

Doesn't 5w30 Dino shear down to about a 5w20 after a couple thousand miles anyway?

PJH · Mar 7, 2006

Dagwood

Then what does 5w20 shear down to after ......?

moribundman · Mar 7, 2006

Don't you know only oil thickening is dangerous?

427Z06 · Mar 7, 2006

quote:

Originally posted by PJH:
Then what does 5w20 shear down to after ......?

Well, using thick-head logic it shouldn't shear down as much. Since the base oils are the same, the "5w" part, the "20" part indicates that there is less viscosity index improvers to shear down.

PJH · Mar 8, 2006

quote:

Originally posted by 427Z06:

quote:

Originally posted by PJH:
Then what does 5w20 shear down to after ......?

Click to expand...

Well, using thick-head logic it shouldn't shear down as much. Since the base oils are the same, the "5w" part, the "20" part indicates that there is less viscosity index improvers to shear down.

Then like 5w15

G-MAN · Mar 8, 2006

quote:

Originally posted by PJH:
Dagwood

Then what does 5w20 shear down to after ......?

Check the UOAs of 5w20s posted on this forum. They don't shear very much, and certainly not out of grade. 5w30s routinely shear out of grade.

hominid7 · Mar 8, 2006

The dealer put 5w20 in my 2001 mazda 2.5 V6 which is spec'd for 5w30 or 10w30. It's one of the few that Ford/Mazda did not back-spec for 5w20.

Anyway, i noticed no adverse effects, and also noticed that on the highway i got one of the best MPG i've ever seen in my car. The engine rev'd freely and there seemed to be no oil usage and no heat problems. However i did dump the oil after 2000 miles as it was getting really hot outside and I didn't want to risk it.

bob_ninja · Mar 8, 2006

G-Man,
Why is that? Why would 5W30s shear down much more than 5W20s? Does it apply to both dino and synth? Is it common accross brands?

How about xW40s and xW50s? Do they shear down a lot?

People here keep saying that contemporary xW20s are so much better (shear stable) than older xW30 formulations. If it is true, what triggered it? Tougher requirements from Ford compared to API and others? Is it a feature of the contemporary base oils and additives, for some reason being much better than in the past or .....? I am just curious why the difference between 20s and 30s.

thanks

G-MAN · Mar 8, 2006

quote:

Originally posted by bob_ninja:
G-Man,
Why is that? Why would 5W30s shear down much more than 5W20s? Does it apply to both dino and synth? Is it common accross brands?

It's a function of the specs that 5w20s have to meet and the way they are made. By using higher VI base oils and the fact that there is less viscosity spread, these oils use less VI improvers. It's the VI improvers that permanently shear causing viscosity loss. 5w30s have more VI improvers. Any oil with over a 20 pt viscosity spread is going to shear some, and some more than others depending on the quality of the base oils and VI improvers used.

All things being equal, a 5w20 is the least likely to shear out of grade of any multi-grade oil, and a 10w40 is the most likely. Even synthetics with wide spreads can shear. The one UOA I've seen of Castrol 10w60 showed it sheard down to a 50wt. Synthetics with little or no VI improvers are the least likely to shear. I don't think we've ever seen Castrol 0w30 shear any at all.

BearZDefect · Mar 9, 2006

1994 Honda Civic 1.5 with 211k mi.
Current fill: Pennz 5w-20 SM/GF4
Prior two fills: Hav 5w-30 SL/GF3

All is well after 1k of the usual short trips. No difference noted either positive or negative. Too cheap to do a UOA, would rather change the oil at 4k instead.

mettech · Mar 9, 2006

89 Honda 2.0.... Recommend 5W-30... I use MC 5W-20. It revs faster and get .5- 1 MPG better.

I think you could use water in it. lol.. Honda makes an excellent engine.

Titan · Mar 9, 2006

My subaru's both call for 5-30. I have some GC, yep, the real green thick 0-30. I'd like to thin it down some and asked Castrol if their syntec 5-20 is OK to mix with the 0-30. No response. I just think the thick 30 weight is overkill, but, don't want to mess around with it too much...might just have to put up with a little less mpg, if that occurs. Just not real sure about some of those additives so many people use in their oil...although if Terry Dyson recommends them and they show good results in Analysis, I shouldn't be too concerned.

427Z06 · Mar 9, 2006

Zaedock · Mar 9, 2006

Check your list again. Some of the ones I looked at were still 30wt's. 15 of the UOA's had a viscosity > 54 @210*F 30wt's are roughly 54-61.

StressSolutions · Mar 9, 2006

A local dealer has printed a coupon for LOF and has printed on the coupon:

"No Extra Charge for 5W20!"

Certainly should not be an extra charge.

427Z06 · Mar 9, 2006

quote:

Originally posted by Zaedock:
Check your list again. Some of the ones I looked at were still 30wt's. 15 of the UOA's had a viscosity > 54 @210*F 30wt's are roughly 54-61.

SUS is old school, baby. I convert to cSt. Anything <= 56.8 SUS, I consider SAE 20, i.e. < 9.3 cSt.

USING 5W-20 WHERE NOT SPECIFIED

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